Apparatuses of this kind are used in particular in systems in which stained specimens or tissue samples, such as a histological section, on specimen slides are provided with a coverslip in order to be analyzed later under a microscope. Staining of the specimens takes place in stainers, in which the specimen slides having the tissue samples are sorted into racks or specimen slide holders and, together with them, immersed into stain containers. During this process, the specimen slides are arranged vertically next to one another in the horizontally oriented rack. The racks used are principally ones in which a rack basket is suspended from a pivotable bail at which the rack can be grasped and transported. This bail also serves as a closure mechanism that prevents unintentional removal of the specimen slides from the rack. After staining, the rack is transferred to a coverslipper, where the coverslipping process takes place.
In stainers as well as in coverslippers, racks are used for storing specimens. In the stainer, the specimen slides are arranged vertically in the rack in order to enable the staining medium to run off the specimen slide in the best possible way. In the coverslipper, the specimen slides are oriented horizontally in order to prevent the coverslipping medium from flowing off the specimen slide. The specimen is oriented upward in that position. In both apparatuses (stainer and coverslipper), the racks are introduced into the respective apparatus through a drawer. During placement of the rack, the orientation of the racks must be identical. Thereby, incorrect positioning by the user is avoided. In addition, there is the need for the specimen to be accessible for the user in case of a failure of the staining process.
Prior to coverslipping, the specimen slides are as a rule first introduced into input cuvettes with solvent (xylene) in order to ensure better flow characteristics for the coverslipping agent used during coverslipping. The rack having the specimen slides is then conveyed to a coverslipping unit where firstly the coverslipping medium (an adhesive or the like) is applied onto the specimen slides, and then the coverslip is put in place to seal off the tissue sample. In order to achieve a maximally optimal process result, the specimen slides must remain vertical in the rack for a long time after staining. At the same time, the coverslipping process demands that the specimen slide be oriented horizontally in order to prevent the coverslipping medium from running off the specimen slide. This requires that the specimen slide be reoriented before coverslipping.
This can be accomplished by pivoting the entire rack 90 degrees from a horizontal position into a vertical position, with the result that the specimen slides, arranged perpendicularly relative to the longitudinal axis of the rack, become horizontally oriented (so-called “rack processing”). The specimen slides are then removed from the rack, and the process of coverslipping the individual specimen slides can begin. Certain coverslipping methods require that the sample on the specimen be oriented upward. In addition, the rack must also be oriented so that the specimen slides can be removed from the rack. An incorrectly inserted rack can mean that the wrong side of the rack is oriented toward the coverslipping unit, and that the coverslipping process cannot begin.
A processing machine, known from WO 95/20176, for applying coverslips onto specimen slides provides a receptacle, serving as an input door, into which a rack having vertically inserted specimen slides can be slid. The receptacle is then swung from an initially horizontal position into a vertical position. A gripper grasps the now horizontally oriented specimen slides, pulls them individually out of the rack, and conveys them to a coverslipping apparatus or unit. A possibility that cannot be precluded, however, is that the rack becomes inserted into the receptacle the wrong way around in the context of rack processing, and that after the rack is brought upright, the sample is arranged on the wrong side of the specimen slide. The rack would then need to be reoriented.
A high level of process reliability must be guaranteed in fully automatic stainers and coverslippers, but also in the context of combination devices such as those known, for example, from DE 101 44 989 B4. This means that the racks are delivered to the coverslipping unit in a correct orientation even if the machines are incorrectly loaded. The tissue sample must be located on the upper side of the specimen slide, and the rack must be correctly oriented. If the incorrect orientation of a rack is not detected and corrected, in the worst case the process must be interrupted and the placement of the rack must be corrected by a laboratory worker. Automatic correction mechanisms are therefore desirable.
DE 100 41 230 A1 discloses a transport device having a robot arm having an end-located gripper that can grasp the racks and lift them along a vertical axis. The transport device is made up of multiple sub-arms, and can rotate and reorient the racks around the vertical axis. This apparatus cannot, however, swing the rack.